Legacy apps aren’t just slow—they’re expensive. Two codebases, a UI that breaks easily, features that don't work, and release days that mess up your plans. BYBOWU updates old iOS and Android apps to Flutter so you can work faster with a single, high-performance codebase that has a clean architecture, a modern UI, and a pipeline that ships on time. You're in the right place if you want to make real progress in 2025 and not just another refactor.
Faster startup time, higher FPS, fewer crashes, and releases in hours—not weeks. Your team works on features instead of putting out fires. Flutter lets you write one codebase that works almost like native on iOS and Android (and even web and desktop if you need it). What happened? More features, faster releases, a lower total cost of ownership, and a mobile experience that your users will love.
- Single codebase, double coverage: Build once for iOS and Android with consistent UX and fewer regressions.
- Performance that feels native: Impeller reduces jank; Skia’s rendering is smooth; isolates and FFI unlock heavy compute and native integrations.
- Modern UI system: Material 3 and Cupertino widgets for brand-consistent, accessible design.
- Maintainability: Clear layers (domain, data, presentation), typed Dart with null safety, and testable modules.
- Faster time to value: Reusable components and shared logic cut delivery time across platforms.
- Future-ready: Add web or desktop when your roadmap calls for it—no rewrite required.
What We Modernize
BYBOWU doesn’t just “port code.” We rebuild the essentials that make your app durable, fast, and easier to evolve as your business grows.
BLoC or Riverpod with Clean Architecture; dependency injection; feature modules; robust error handling and offline flows.
Design tokens, component library, theming, motion, and accessibility—built on Material 3/Cupertino with golden tests.
Retrofit/dio, GraphQL, offline caching, secure storage, and analytics foundations without performance penalties.
Platform Channels/Pigeon for payments, camera, Bluetooth, maps, biometrics—plus federated plugins for a clean boundary.
Unit/widget/integration testing, codegen and linting, GitHub Actions/Codemagic/fastlane, and release automation.
Our Migration Process
No two legacy apps are the same. We make a migration plan that keeps uptime high, lowers risk, and shows wins early on so that stakeholders can see progress instead of just promises.
- Discovery and audit: We look over your codebases, crash logs, performance metrics (cold start, TTI, FPS, memory), release process, and roadmap. We agree on the business KPIs that drive activation, retention, NPS, and revenue.
- Architecture and plan: Pick BLoC or Riverpod, and then set up modules, API contracts, navigation, and caching. We choose the migration path: either greenfield Flutter or "add-to-app" to add Flutter to your existing native app.
- Incremental delivery: Start with a feature that has a big impact (like onboarding, product detail, or account) to check performance and analytics, and then add more modules. Use Platform Channels or Pigeon to connect to native SDKs (payments, maps, camera, Bluetooth). We keep the edges clean so that future updates will work.
- Performance hardening: Use DevTools to profile your code; optimize builds, image decode paths, and shader warm-up; use Impeller to cut down on jank; and manage isolates for heavy tasks.
- Quality & security: Unit/widget/integration tests; golden tests for UI; static analysis; secure storage; jailbreak/root checks; SSL pinning where appropriate.
- CI/CD & release: GitHub Actions or Codemagic pipelines, fastlane lanes, beta distribution (TestFlight/Play Internal), staged rollouts, and crash/ANR monitoring.
- Handover and growth: Documentation, training, and a list of things to do in the next 90 days. We can keep working as your feature team or help your developers.
Benefits You Can Measure
30–60% faster cold start, smoother scroll and animations, fewer ANRs/crashes, leaner battery usage.
Single backlog and codebase; features shipped to both platforms in one sprint; fewer merge conflicts and regressions.
Typed Dart with null safety, modular code, shared design system, and automated tests you can trust.
Reduce duplicated work, app store review cycles, and patch fire drills. Your money goes to the product, not to fixing it.
FAQs
Is it possible to move from native apps to Flutter?
Yes, and in a lot of cases, it's the quickest way to stabilize and grow. We usually start with an "add-to-app" approach, which means putting Flutter screens into your existing native shell to make the move less risky. Once we know that everything is stable and works well, we finish the migration feature by feature. You can still use Platform Channels or Pigeon to access native features, and you don't have to give up any of your mission-critical SDKs.
Will Flutter match native performance?
For most purposes, well-built Flutter apps are just as good as native apps. The UI stays smooth and responsive with Impeller and best practices like shader warm-up, efficient rebuilds, and background isolates. We send GPU- and CPU-heavy tasks to native or FFI as needed.
How do you deal with big apps and complicated SDKs?
We break up the codebase into smaller pieces, keep a list of plugins, and make federated plugins for complicated SDKs like payments, streaming, and BLE. We keep the boundaries strict so that changes don't affect the whole app.
What about the size of the app and its ability to work offline?
We make assets as small as possible, split them up by ABI, and cut down on dependencies to keep the bundle size down. We use caching strategies, background sync, conflict resolution, and resilient error states to make things work offline.
How do you make sure the quality stays high after launch?
Crash monitoring, ANR tracking, performance dashboards, synthetic tests, and alerts for release health. We can work as your long-term feature team if you'd like, and we set aside time for maintenance.
Ready to ship faster with one codebase and a modern UI that your users love? We will look over your current app, suggest options that are aware of risks, and give you a timeline and budget that you can use. Email [email protected] or use our contact form to get in touch with us. Want to see how we've done it in the past? Check out our portfolio to see some of our wins. Action first: We focus on the modules that will move KPIs—activation, retention, and revenue—within the first sprint.